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 // Copyright (C) 2011 Thiago Macieira <thiago@kde.org>
 // Copyright (C) 2016 Intel Corporation.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
 #ifndef QATOMIC_CXX11_H
 #define QATOMIC_CXX11_H
 
 #include <QtCore/qgenericatomic.h>
 #include <QtCore/qyieldcpu.h>
 #include <atomic>
 
 QT_BEGIN_NAMESPACE
 
 #if 0
 // silence syncqt warnings
 QT_END_NAMESPACE
 #pragma qt_sync_skip_header_check
 #pragma qt_sync_stop_processing
 #endif
 
 /* Attempt to detect whether the atomic operations exist in hardware
  * or whether they are emulated by way of a lock.
  *
  * C++11 29.4 [atomics.lockfree] p1 says
  *
  *  The ATOMIC_..._LOCK_FREE macros indicate the lock-free property of the
  *  corresponding atomic types, with the signed and unsigned variants grouped
  *  together. The properties also apply to the corresponding (partial)
  *  specializations of the atomic template. A value of 0 indicates that the
  *  types are never lock-free. A value of 1 indicates that the types are
  *  sometimes lock-free. A value of 2 indicates that the types are always
  *  lock-free.
  *
  * We have a problem when the value is 1: we'd need to check at runtime, but
  * QAtomicInteger requires a constexpr answer (defect introduced in Qt 5.0). So
  * we'll err in the side of caution and say it isn't.
  */
 template <int N> struct QAtomicTraits
 { static inline bool isLockFree(); };
 
 #define Q_ATOMIC_INT32_IS_SUPPORTED
 #if ATOMIC_INT_LOCK_FREE == 2
 #  define Q_ATOMIC_INT_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT_TEST_AND_SET_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT32_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT32_TEST_AND_SET_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 
 template <> inline bool QAtomicTraits<4>::isLockFree()
 { return true; }
 #elif ATOMIC_INT_LOCK_FREE == 1
 #  define Q_ATOMIC_INT_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT32_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT32_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 
 template <> inline bool QAtomicTraits<4>::isLockFree()
 { return false; }
 #else
 #  define Q_ATOMIC_INT_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT_TEST_AND_SET_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_STORE_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT_FETCH_AND_ADD_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT32_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT32_TEST_AND_SET_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_STORE_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT32_FETCH_AND_ADD_IS_NEVER_NATIVE
 
 template <> inline bool QAtomicTraits<4>::isLockFree()
 { return false; }
 #endif
 
 #if ATOMIC_POINTER_LOCK_FREE == 2
 #  define Q_ATOMIC_POINTER_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_POINTER_TEST_AND_SET_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 #elif ATOMIC_POINTER_LOCK_FREE == 1
 #  define Q_ATOMIC_POINTER_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_POINTER_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 #else
 #  define Q_ATOMIC_POINTER_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #  define Q_ATOMIC_POINTER_TEST_AND_SET_IS_NEVER_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_STORE_IS_NEVER_NATIVE
 #  define Q_ATOMIC_POINTER_FETCH_AND_ADD_IS_NEVER_NATIVE
 #endif
 
 template<> struct QAtomicOpsSupport<1> { enum { IsSupported = 1 }; };
 #define Q_ATOMIC_INT8_IS_SUPPORTED
 #if ATOMIC_CHAR_LOCK_FREE == 2
 #  define Q_ATOMIC_INT8_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT8_TEST_AND_SET_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 
 template <> inline bool QAtomicTraits<1>::isLockFree()
 { return true; }
 #elif ATOMIC_CHAR_LOCK_FREE == 1
 #  define Q_ATOMIC_INT8_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT8_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 
 template <> inline bool QAtomicTraits<1>::isLockFree()
 { return false; }
 #else
 #  define Q_ATOMIC_INT8_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT8_TEST_AND_SET_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_STORE_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT8_FETCH_AND_ADD_IS_NEVER_NATIVE
 
 template <> bool QAtomicTraits<1>::isLockFree()
 { return false; }
 #endif
 
 template<> struct QAtomicOpsSupport<2> { enum { IsSupported = 1 }; };
 #define Q_ATOMIC_INT16_IS_SUPPORTED
 #if ATOMIC_SHORT_LOCK_FREE == 2
 #  define Q_ATOMIC_INT16_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT16_TEST_AND_SET_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 
 template <> inline bool QAtomicTraits<2>::isLockFree()
 { return false; }
 #elif ATOMIC_SHORT_LOCK_FREE == 1
 #  define Q_ATOMIC_INT16_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT16_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 
 template <> inline bool QAtomicTraits<2>::isLockFree()
 { return false; }
 #else
 #  define Q_ATOMIC_INT16_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT16_TEST_AND_SET_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_STORE_IS_NEVER_NATIVE
 #  define Q_ATOMIC_INT16_FETCH_AND_ADD_IS_NEVER_NATIVE
 
 template <> inline bool QAtomicTraits<2>::isLockFree()
 { return false; }
 #endif
 
 #if !defined(QT_BOOTSTRAPPED) && QT_CONFIG(std_atomic64)
 template<> struct QAtomicOpsSupport<8> { enum { IsSupported = 1 }; };
 #  define Q_ATOMIC_INT64_IS_SUPPORTED
 #  if ATOMIC_LLONG_LOCK_FREE == 2
 #    define Q_ATOMIC_INT64_REFERENCE_COUNTING_IS_ALWAYS_NATIVE
 #    define Q_ATOMIC_INT64_TEST_AND_SET_IS_ALWAYS_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_STORE_IS_ALWAYS_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_ADD_IS_ALWAYS_NATIVE
 
 template <> inline bool QAtomicTraits<8>::isLockFree()
 { return true; }
 #  elif ATOMIC_LLONG_LOCK_FREE == 1
 #    define Q_ATOMIC_INT64_REFERENCE_COUNTING_IS_SOMETIMES_NATIVE
 #    define Q_ATOMIC_INT64_TEST_AND_SET_IS_SOMETIMES_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_STORE_IS_SOMETIMES_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_ADD_IS_SOMETIMES_NATIVE
 
 template <> inline bool QAtomicTraits<8>::isLockFree()
 { return false; }
 #  else
 #    define Q_ATOMIC_INT64_REFERENCE_COUNTING_IS_NEVER_NATIVE
 #    define Q_ATOMIC_INT64_TEST_AND_SET_IS_NEVER_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_STORE_IS_NEVER_NATIVE
 #    define Q_ATOMIC_INT64_FETCH_AND_ADD_IS_NEVER_NATIVE
 
 template <> inline bool QAtomicTraits<8>::isLockFree()
 { return false; }
 #  endif
 #endif
 
 template <typename X> struct QAtomicOps
 {
     typedef std::atomic<X> Type;
 
     template <typename T> static inline
     T load(const std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T load(const volatile std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T loadRelaxed(const std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T loadRelaxed(const volatile std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T loadAcquire(const std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T loadAcquire(const volatile std::atomic<T> &_q_value) noexcept
     {
         return _q_value.load(std::memory_order_acquire);
     }
 
     template <typename T> static inline
     void store(std::atomic<T> &_q_value, T newValue) noexcept
     {
         _q_value.store(newValue, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     void storeRelaxed(std::atomic<T> &_q_value, T newValue) noexcept
     {
         _q_value.store(newValue, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     void storeRelease(std::atomic<T> &_q_value, T newValue) noexcept
     {
         _q_value.store(newValue, std::memory_order_release);
     }
 
     static inline bool isReferenceCountingNative() noexcept { return isTestAndSetNative(); }
     static inline constexpr bool isReferenceCountingWaitFree() noexcept { return false; }
     template <typename T>
     static inline bool ref(std::atomic<T> &_q_value)
     {
         /* Conceptually, we want to
          *    return ++_q_value != 0;
          * However, that would be sequentially consistent, and thus stronger
          * than what we need. Based on
          * http://eel.is/c++draft/atomics.types.memop#6, we know that
          * pre-increment is equivalent to fetch_add(1) + 1. Unlike
          * pre-increment, fetch_add takes a memory order argument, so we can get
          * the desired acquire-release semantics.
          * One last gotcha is that fetch_add(1) + 1 would need to be converted
          * back to T, because it's susceptible to integer promotion. To sidestep
          * this issue and to avoid UB on signed overflow, we rewrite the
          * expression to:
          */
         return _q_value.fetch_add(1, std::memory_order_acq_rel) != T(-1);
     }
 
     template <typename T>
     static inline bool deref(std::atomic<T> &_q_value) noexcept
     {
         // compare with ref
         return _q_value.fetch_sub(1, std::memory_order_acq_rel) != T(1);
     }
 
     static inline bool isTestAndSetNative() noexcept
     { return QAtomicTraits<sizeof(X)>::isLockFree(); }
     static inline constexpr bool isTestAndSetWaitFree() noexcept { return false; }
 
     template <typename T>
     static bool testAndSetRelaxed(std::atomic<T> &_q_value, T expectedValue, T newValue, T *currentValue = nullptr) noexcept
     {
         bool tmp = _q_value.compare_exchange_strong(expectedValue, newValue, std::memory_order_relaxed, std::memory_order_relaxed);
         if (currentValue)
             *currentValue = expectedValue;
         return tmp;
     }
 
     template <typename T>
     static bool testAndSetAcquire(std::atomic<T> &_q_value, T expectedValue, T newValue, T *currentValue = nullptr) noexcept
     {
         bool tmp = _q_value.compare_exchange_strong(expectedValue, newValue, std::memory_order_acquire, std::memory_order_acquire);
         if (currentValue)
             *currentValue = expectedValue;
         return tmp;
     }
 
     template <typename T>
     static bool testAndSetRelease(std::atomic<T> &_q_value, T expectedValue, T newValue, T *currentValue = nullptr) noexcept
     {
         bool tmp = _q_value.compare_exchange_strong(expectedValue, newValue, std::memory_order_release, std::memory_order_relaxed);
         if (currentValue)
             *currentValue = expectedValue;
         return tmp;
     }
 
     template <typename T>
     static bool testAndSetOrdered(std::atomic<T> &_q_value, T expectedValue, T newValue, T *currentValue = nullptr) noexcept
     {
         bool tmp = _q_value.compare_exchange_strong(expectedValue, newValue, std::memory_order_acq_rel, std::memory_order_acquire);
         if (currentValue)
             *currentValue = expectedValue;
         return tmp;
     }
 
     static inline bool isFetchAndStoreNative() noexcept { return isTestAndSetNative(); }
     static inline constexpr bool isFetchAndStoreWaitFree() noexcept { return false; }
 
     template <typename T>
     static T fetchAndStoreRelaxed(std::atomic<T> &_q_value, T newValue) noexcept
     {
         return _q_value.exchange(newValue, std::memory_order_relaxed);
     }
 
     template <typename T>
     static T fetchAndStoreAcquire(std::atomic<T> &_q_value, T newValue) noexcept
     {
         return _q_value.exchange(newValue, std::memory_order_acquire);
     }
 
     template <typename T>
     static T fetchAndStoreRelease(std::atomic<T> &_q_value, T newValue) noexcept
     {
         return _q_value.exchange(newValue, std::memory_order_release);
     }
 
     template <typename T>
     static T fetchAndStoreOrdered(std::atomic<T> &_q_value, T newValue) noexcept
     {
         return _q_value.exchange(newValue, std::memory_order_acq_rel);
     }
 
     static inline bool isFetchAndAddNative() noexcept { return isTestAndSetNative(); }
     static inline constexpr bool isFetchAndAddWaitFree() noexcept { return false; }
 
     template <typename T> static inline
     T fetchAndAddRelaxed(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_add(valueToAdd, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T fetchAndAddAcquire(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_add(valueToAdd, std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T fetchAndAddRelease(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_add(valueToAdd, std::memory_order_release);
     }
 
     template <typename T> static inline
     T fetchAndAddOrdered(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_add(valueToAdd, std::memory_order_acq_rel);
     }
 
     template <typename T> static inline
     T fetchAndSubRelaxed(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_sub(valueToAdd, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T fetchAndSubAcquire(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_sub(valueToAdd, std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T fetchAndSubRelease(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_sub(valueToAdd, std::memory_order_release);
     }
 
     template <typename T> static inline
     T fetchAndSubOrdered(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_sub(valueToAdd, std::memory_order_acq_rel);
     }
 
     template <typename T> static inline
     T fetchAndAndRelaxed(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_and(valueToAdd, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T fetchAndAndAcquire(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_and(valueToAdd, std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T fetchAndAndRelease(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_and(valueToAdd, std::memory_order_release);
     }
 
     template <typename T> static inline
     T fetchAndAndOrdered(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_and(valueToAdd, std::memory_order_acq_rel);
     }
 
     template <typename T> static inline
     T fetchAndOrRelaxed(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_or(valueToAdd, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T fetchAndOrAcquire(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_or(valueToAdd, std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T fetchAndOrRelease(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_or(valueToAdd, std::memory_order_release);
     }
 
     template <typename T> static inline
     T fetchAndOrOrdered(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_or(valueToAdd, std::memory_order_acq_rel);
     }
 
     template <typename T> static inline
     T fetchAndXorRelaxed(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_xor(valueToAdd, std::memory_order_relaxed);
     }
 
     template <typename T> static inline
     T fetchAndXorAcquire(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_xor(valueToAdd, std::memory_order_acquire);
     }
 
     template <typename T> static inline
     T fetchAndXorRelease(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_xor(valueToAdd, std::memory_order_release);
     }
 
     template <typename T> static inline
     T fetchAndXorOrdered(std::atomic<T> &_q_value, typename QAtomicAdditiveType<T>::AdditiveT valueToAdd) noexcept
     {
         return _q_value.fetch_xor(valueToAdd, std::memory_order_acq_rel);
     }
 };
 
 #  define Q_BASIC_ATOMIC_INITIALIZER(a)     { a }
 
 QT_END_NAMESPACE
 
 #endif // QATOMIC_CXX0X_H

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